Trunks first appears as an unknown young man who easily defeats Freeza and his father, before Goku arrives back on Earth. Spoiler!It is then revealed that he is Vegeta and Bulma's future child, who has traveled back in time to inform Goku of the coming of the Androids, whom in his time have killed everyone including Goku. He helps fight against the Androids and later Cell, before returning to his own time.

Just as the Androids arrived, the Trunks from the series' main timeline was born. Seven years later as a young kid, Trunks, already able to turn Super Saiyan despite his age, fights against Majin Boo as Gotenks, having used the fusion technique with Goten.